Perpetual calendar



FIG. 1 is a side elevation view of a perpetual calendar showing my newdesign, and showing the obverse side of each of the date slides;

FIG. 2 is a plan view thereof;

FIG. 3 is an end view thereof; and

FIG. 4 is a side view thereof showing the reverse side of each of thedate slides.

The rear of the slide holder is plain and unornamented.

The ornamental design for a perpetual calendar, as shown and described.